Dead mice and duct cleaning

I am convinced that my air ducts are contaminated with dead mice.   During the Winter, my whole home tends to smell way too much like I’m cooking dead mice. I always have traps and poison set up, and I watch for mice all year. I even hire an HVAC supplier for professional air duct cleaning. They use  special equipment to brush away and suck up the debris from inside the HVAC ducts. I clean my carpets, wash all my curtains, clean the windows and wash every surface with disinfectant. My home smells great for maybe a week. Then I activate the heating unit and my home reeks. I must have lots of mice hiding in my home. Once a mouse starts to get old, it must decide to die in my HVAC ducts. It could be that my heating system murders them. Perhaps the mice vacate the HVAC duct system when they notice the arrival of the HVAC van. They let the HVAC technician  perform the duct cleaning. Then they move back in once he’s done. I bet they like are thrilled that their home got a thorough cleaning. I bet they move right back in until I cook them alive with my gas furnace. I just don’t know what to do about it. I never can catch them in the air duct until they are already dead. I also can’t go without my furnace in the Winter. An air cleaner might help, but the odor is super foul. I would rather fix the air quality issue at the source. I can’t let the mice live in the air ducts. They can’t contaminate my HVAC system and air quality.  

indoor air quality